Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare this as a safe, non-destructive, closed-world read. The description adds behavior beyond them: default ordering (newest first) and the default exclusion of archived diagrams, plus the citation rendering convention. It stops short of describing pagination or result limits, so it is strong but not exhaustive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, zero filler, and the core purpose is front-loaded before the parameter notes and the cross-tool pointer. The citation rule is separated into its own high-salience clause ('NEVER cite a diagram as [[board:ID]]'), which is the right structure for a formatting constraint the agent must obey.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the return-shape burden, and it does convey that diagram records (with IDs, per the [[diagram:ID]] convention) come back in a defined order. It omits pagination or result-size behavior and says nothing about the `workspace` parameter, which is a real gap for a no-required-parameter listing tool, but overall an agent has enough to call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents `q`, `workspace`, and `includeArchived`; the description restates the effect of `q` and `includeArchived` without adding format or syntax detail. The `workspace` parameter, with its non-obvious token/default rules, is not mentioned in the description at all. Baseline 3 is appropriate when the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (lists), resource (the workspace's Napkin diagrams), defines what the resource is with examples (interactive flowcharts — processes, decision trees, system maps), and specifies ordering (newest first). It also disambiguates from the adjacent napkin_boards concept by warning that boards are sketches, so an agent can separate the two resource families without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives explicit conditions for the optional behaviors: archived items are hidden unless `includeArchived`, and `q` narrows by title. It routes to the sibling that supplies more detail ('Fetch one's mermaid source with napkin_diagrams_get'), which is exactly the when-to-use-the-other-tool guidance an agent needs.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.